System for making abrasive article

ABSTRACT

In some examples, an abrasive particle transfer system including a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening; abrasive particles removably disposed within at least some of the cavities such that a portion of each particle protrudes from the back surface through the second opening; and a transfer roll having an outer surface, wherein the production tool is guided along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts the outer surface of the abrasive particle transfer roll to displace the abrasive particles.

TECHNICAL FIELD

The present disclosure relates to abrasive articles including abrasive particles, and methods of making the same.

BACKGROUND

Abrasive articles generally include abrasive particles (also known as “grains”) retained in a binder. During manufacture of various types of abrasive articles, the shaped abrasive particles are deposited on a binder material precursor in an oriented manner (e.g., by electrostatic coating or by some mechanical placement technique). Typically, the most desirable orientation of the shaped abrasive particles is substantially perpendicular to the surface of the backing.

In a coated abrasive article (e.g., sandpaper), the backing is a relatively dense planar substrate. A make layer precursor (or make coat) containing a first binder material precursor is applied to the backing, and then the shaped abrasive particles are partially embedded into the make layer precursor. In some embodiments, the shaped abrasive particles, which have a shape selected for a particular sanding or grinding application, are embedded in the make layer precursor with a preferred orientation. Suitable techniques or orienting the particles include, for example, electrostatic coating or a mechanical placement technique.

The make layer precursor is then at least partially cured to retain the oriented shaped abrasive particles when a size layer precursor (or size coat) containing a second binder material precursor is overlaid on the at least partially cured make layer precursor and oriented shaped abrasive particles. The size layer precursor, and the make layer precursor can then be further cured if needed to form a coated abrasive article.

SUMMARY

As described herein, examples of the disclosure relate to systems and techniques for manufacturing abrasive articles including, for example, abrasive particles adhered to a resin coated backing or other substrate. In some examples, a particle transfer system may be configured to transfer abrasive particles removably disposed in cavities of a production tool to a resin coated backing or other substrate which it is desirable to transfer abrasive particles. The abrasive particles may be removably disposed within at least some of the cavities in a desired orientation and pattern.

As will be described below, the production tool may include a dispensing surface and a back surface opposite the dispensing surface. The respective cavities may extend from a first opening in the dispensing surface through the production tool to a second opening in the back surface of the production tool that is smaller than the first opening. The shape and size of the openings in the production tool relative to the shape and size of the abrasive particles allows for a portion of each of the abrasive particles to protrude from the bottom surface of the production tool while the abrasive particles are removably disposed within respective cavities.

During the particle transfer process, the production tool may be guided along a first web path such that the back surface of the production tool is adjacent a transfer roll and an outer surface of the transfer roll contacts the protruding portion of the abrasive particles within the respective cavities of the production tool. The contact from the outer surface to the protruding portion displaces the particles disposed with the respective cavities. In some examples, the displacement of the particle may cause the particle to be transferred out of the cavity onto a substrate (e.g., a resin coated backing) adjacent the dispensing surface of the production tool.

In one example, the disclosure relates to an abrasive particle transfer system comprising:

a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening;

abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and an abrasive particle transfer roll having an outer surface, wherein the production tool is guided along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts the outer surface of the abrasive particle transfer roll to displace the abrasive particles.

In another example, the disclosure relates to a method of transferring abrasive particles, the method comprising:

providing a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening, wherein abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and guiding the production tool along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts an outer surface of an abrasive particle transfer roll to displace the abrasive particles.

Features and advantages of the present disclosure will be further understood upon consideration of the detailed description as well as the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating an example abrasive particle transfer system according to an example of the disclosure.

FIG. 2 is a conceptual diagram illustrating an example abrasive particle disposed within a cavity of a production tool.

FIG. 3 is a conceptual diagram illustrating the example abrasive particle of FIG. 2 in contact with an outer surface of a transfer roll.

FIG. 4 is a conceptual diagram illustrating an example abrasive particle being transferred to an adjacent substrate.

FIG. 5 is a conceptual diagram illustrating an example production tool from a top view.

FIG. 6 is a conceptual diagram illustrating a cross-section view of the example production tool of FIG. 5 along cross-section A-A.

FIG. 7 is a conceptual diagram illustrating another example abrasive particle disposed within a cavity of a production tool.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure.

DETAILED DESCRIPTION

As describe above, examples of the disclosure relate to systems and techniques for manufacturing abrasive articles including, for example, abrasive particles adhered to a resin coated backing or other substrate.

Shaped abrasive particles may be transferred to an adhesive resin coated substrate surface such that the particles maintain a specific pattern and orientation with respect to the optimal cutting configuration. The pattern and orientation may be achieved by employing of a patterned transfer tooling (also referred to as a “production tool”) including cavities that are filled with the loose abrasive particles. The transfer tooling may then be inverted to allow the particles to drop out of the cavities from the dispensing surface onto an opposing surface of resin coated substrate under the force of gravity. However, in some instances, rather than dropping onto the surface of the resin coated substrate from the dispensing surface of the tooling, at least some of the abrasive particles may become stuck within the respective cavities of the tooling, e.g., due to mechanical and/or static forces.

In accordance with one or more examples of the disclosure, a production tool may be configured such that a portion of each abrasive particle extends out of an opening in the back surface of a tooling opposite that of the dispensing surface when the abrasive particles are disposed within respective cavities. During the transfer process, the outer surface of a transfer roll may be brought into contact with the portion of the abrasive particles protruding from the back surface of the production tool to displace the abrasive particle disposed in the cavity. In some examples, the displacement of the abrasive particle may eject or other cause the contacted particles to be removed from the respective cavities of the production tool, e.g., alone or in combination with one or more other forces urging the particles out of the respective cavities. In some examples, employing such a technique may allow for more effective and/or more accurate removal of individual abrasive particles from the production tool, e.g., during transfer of abrasive particles to an opposing substrate. In some examples, such advantageous may provide for increased process stability.

FIG. 1 is a conceptual diagram illustrating an example abrasive particle transfer system 10 according to an example of the disclosure. As shown in FIG. 1, system 10 includes production tool 12, individual abrasive particles 14 a, 14 b, 14 c (collectively abrasive particles 14) removably disposed in respective cavities 16 of production tool 12, and transfer roll 18. As will be described further below, when removably disposed in cavities 16, portions of abrasive particles 14 a, 14 b, and 14 c protrude through second opening 26 in back surface 24 of production tool 12. When production tool 20 is guided along web path 20, outer surface 19 of transfer roll 18 contacts this protruding portion of the abrasive particle, e.g., as shown for abrasive particle 14 b in FIG. 1, to displace the abrasive particle. The displacement of the abrasive particle may assist or otherwise result in the removal of the abrasive particle from the cavity in production tool.

The relative size of particles 14 shown FIG. 1 have been enlarged from that of some embodiments for ease of illustration. Further, as will be apparent from the description, the view of production tool 12 shown in FIG. 1 is a cross-section in the x-z plane to illustrate the disposition of particles 14 within respective cavities 16 (e.g., in the portion of production tool 12 that has not contacted outer surface 18 of transfer roll 18 along web path 20) as well as cavities 16 which do not contain one of particles 14 (e.g., in the portion of production tool 12 that has contacted outer surface 18 of transfer roll 18 along web path 20).

Abrasive particle transfer system 10 may be employed in a larger system for making abrasive articles. For example, an abrasive particle transfer system 10 may be utilized with an abrasive particle feeder that is configured to supply abrasive particles to production tool 12 prior to being guided along web path 20 around transfer roll 18. In some examples, the feeder may supply an excess of abrasive particles helps to ensure all cavities within the production tool 20 are eventually filled with an abrasive particle. Optionally, a filling assist member may be provided after the abrasive particle feeder to move the abrasive particles around on the dispensing surface 22 of the production tool 12 and to help orientate or slide the abrasive particles 14 into the cavities 16. Examples of systems for making abrasive articles which may utilize examples of the abrasive particles system 10 described herein to transfer abrasive particles to a substrate, e.g., a resin coated backing, may include one or more of the examples described in PCT published patent application WO2015/100220, the entire content of which is incorporated herein by reference. However, other examples are contemplated.

FIG. 5 is a conceptual diagram illustrating an example of production tool 12 from a top view, i.e., a view of the dispensing surface 22 of production tool 12. As shown, production tool 12 includes a plurality of discrete cavities 16 (only two individual cavities 16 are labelled) formed therein to define d. As will be apparent from the description herein, the plurality of cavities 16 may have a complimentary shape to the intended abrasive particle to be contained therein. For ease of illustration, production tool 12 is shown as including a relatively simple arrangement of three cavities 16 per row in the cross-web direction defined in production tool 12. The arrangement and shape of cavities 16 in production tool 12 may be selected based on the desired pattern and orientation of abrasive particles 14 transferred from production tool 12 to the surface of another substrate in the manner described herein.

FIG. 6 is a conceptual diagram illustrating a cross-section view of the example production tool of FIG. 5 along cross-section A-A. As shown, cavity 16 extends from a first opening 28 at the dispensing surface 22 through production tool 12 to a second opening 26 at the back surface 24 of production tool 12. Second opening 26 may be smaller than first opening, e.g., such that particles 14 having a desired shape and size may be removably disposed within cavity 16 rather than falling through both first opening 28 and second opening 26 or being too large to fit within first opening 28 and second opening 26. In the illustrated example, first and second opening 28, 26 may have rectangular cross-sections (taken along the x-y axis plane) in which the walls extending from the first opening 28 to the second opening 26 taper inwardly such that the width 42 of first opening 28 is greater than the width 40 of second opening 26. Suitable shapes and sizes for cavities 16 in production tool may include those described in described in PCT published patent application WO2015/100220. While the respective openings of the cavities at the dispensing and back surfaces of the production tool are rectangular, this is not a requirement. The length, width, and depth of the cavities in the carrier member will generally be determined at least in part by the shape and size of the abrasive particles with which they are to be used. Although the two sides of the particles in, e.g., FIGS. 1, 2, and 7 are shown as not touching or in contact with the adjacent sides of the cavity (e.g., as the other sides of the particles not shown in the cross-section may be in contact with the cavity), when the particles are removably disposed in a cavity, at least a portion of the particle may be in contact with one or more cavity walls. The contact may be a result of gravitational force, vacuum, or other force acting on the particle.

As described herein, abrasive particles 14 may be introduced into at least some cavities 16 of production tool 20 for later transfer to the surface of a substrate, e.g., a resin coated backing. The abrasive particles can be disposed within the cavities of the production tool using any suitable technique. Examples include dropping the abrasive particles onto the production tool while it is oriented with the dispensing surface facing upward, and then agitating the particles sufficiently to cause them to fall into the cavities. Examples of suitable agitation methods may include, brushing, blowing, vibrating, applying a vacuum (for carrier members having cavities with openings at the back surface), and combinations thereof. In typical use, abrasive particles are removably disposed within at least a portion, preferably at least 50, 60, 70, 80, 90 percent or even 100 percent of the cavities in the production tool.

In accordance with examples of the disclosure, when an abrasive particle is removably disposed in cavity of the production tool, a portion of the particle may protrude from the back surface of the production tool out of the second opening the cavity. Such an arrangement may be achieved based on the shape and size of a cavity relative the shape and size of the desired abrasive particle.

As an example, FIG. 2 is a magnified view of particle 14 a shown in FIG. 1. As shown in FIG. 2, particle 14 a is disposed within individual cavity 16 of production tool 12. Portion 34 of particle 14 a protrudes from back surface 24 of production tool 12 through second opening 26. The protruding portion 34 of particle 14 a will subsequently be contacted by outer surface 19 of transfer roll 18 when production tool is guided along web path 20. In the example of FIG. 2, portion 34 of particle 14 a protrudes out of back surface 24 to a protrusion height 30. Protrusion height 30 may be any suitable distance. For example, the protrusion height may be at least some minimum distance that allows for contract with the outer surface of the transfer roll to displace the abrasive particle that is in the cavity. In some examples, protrusion height 30 may be at least about 0.001 inches, at least about 0.005 inches, at least about 0.025 inches, about 0.001 inches to about 0.050 inches, about 0.005 inches to about 0.025 inches, about 0.025 inches to about 0.05 inches, or about 0.001 inches to about 0.005 inches.

FIG. 3 is a magnified view of particle 14 b shown in FIG. 1. As shown in FIG. 3, protruding portion 34 of particle 14 b in cavity 16 is contacted by outer surface 19 of transfer roll 18 when production tool 12 is guided along path 20 over transfer roll 18. The contact by the outer surface 19 of transfer roll 18 displaces particle 14 b. The outer surface 19 of transfer roll may be relatively hard so as to prevent protruding portion 34 of particle 14 b from substantially compressing into the surface rather than being displaced by the contact. In the example of FIG. 3, the displace of particle 14 b includes raising the relative position of particle 14 b in cavity 16 in the z-axis direction such that portion 34 of particle 14 b no longer protrudes from the back surface 24 of production tool 34, e.g., on the basis of outer surface 19 being in contact with back surface 24 of production tool 34 as the production tool 34 is guided over transfer roll 18.

In some examples, the displacement of abrasive particle 14 b may cause abrasive particle to protrude from the dispensing surface 22 at least about 0.001 inches, at least about 0.01 inches, about 0.001 inches to about 0.025 inches, or about 0.010 inches to about 0.020 inches.

In some examples, the displacement of abrasive particle 14 b may reposition abrasive particle 34 relative to the volume of cavity 16.

In some examples, the displacement of abrasive particle 14 b may eject or otherwise result in the removal of abrasive particle 34 from cavity 16, either alone or in combination with other forces, e.g., gravitational force or the cessation of a vacuum force.

In some examples, the displacement of abrasive particle 14 b may remove particle 14 b from cavity 16 in a case in which particle 14 b would have remained disposed in cavity 16 e.g., due to mechanical and/or static forces, without the contact with transfer roll 18.

Referring to FIG. 4, the displacement of abrasive particle 14 b from the contact between the protruding portion 34 and outer surface 19 of transfer roll 18 results in the opposing surface of particle 14 b being brought into contact with a resin layer 38 coated on backing 36, which is positioned opposite the dispensing surface 22 of production tool. As shown, such contact may be the result of the position of particle 14 b being generally increased in the z-axis direction out of the dispensing surface 22. The contact with resin layer 38 may be sufficient to transfer particle 14 b to the resin coated backing by adhering the particle 14 b to backing 36 via resin layer 38.

As shown in the configuration of FIG. 4, in some examples, abrasive particle 14 b may be advantageously transferred from cavity 16 to resin coated backing 36 without resin coating 38 being brought into contact with dispensing surface 22 of production tool 12. Instead, as shown in FIG. 4, resin coating 28 and dispensing surface 22 are separated by gap 40. Such a configuration may prevent or reduce resin transfer onto the tooling belt. In some examples, the gap 40 may be accomplished by using the outer surface 19 of the transfer roll 18 to supply the upward support of the particle 14 b shown in FIG. 4. Since the flat surface of the triangle may also be against the resin coated backing, the dispensing surface of the production tool itself would not be able to press against the resin coated backing. In some examples, gap 40 may be at greater than zero, at least about 0.001 inches, at least about 0.005 inches, greater than zero to about 0.050 inches, about 0.001 inches to about 0.050 inches, or about 0.005 inches to about 0.025 inches. In other examples, there may be no gap between the resin coating 28 and dispensing surface 22, and dispensing surface 22 and resin coating 28 may be in contact with each other. In some examples, a phenolic pressure sensitive adhesive may be used as resin coating 28 for configurations in which dispensing surface 22 and resin coating 28 are in contact with each other without gap 40.

Referring to FIG. 2, particle 14 a may also protrude from dispensing surface 22 to height 32 when removably disposed in cavity 16 of production tool 12. In some examples, protrusion height 30 may be at least about 0.001 inches, at least about 0.005 inches, about 0.001 inches to about 0.025 inches, or about 0.005 inches to about 0.025 inches.

Referring to FIG. 7, particle 14 a may also be recessed into dispensing surface 22 to distance 42 when removably disposed in cavity 16 of production tool 12. In some examples, recess distance 42 may be at least about 0.001 inches, at least about 0.002 inches, about 0.001 inches to about 0.025 inches, or about 0.002 inches to about 0.010 inches.

As another example, particle 14 a may be substantially planar with dispensing surface 22 when removably disposed in cavity 16 of production tool 12.

Suitable example production tools of the disclosure may be rigid or flexible, but preferably are sufficiently flexible to permit use of normal web handling devices such as rollers. Preferably, the production tool comprises metal and/or organic polymer. Such organic polymers are preferably moldable, have low cost, and are reasonably durable when used in the abrasive particle deposition process of the present disclosure. Examples of organic polymers, which may be thermosetting and/or thermoplastic, that may be suitable for fabricating the carrier member include: polypropylene, polyethylene, vulcanized rubber, polycarbonates, polyamides, acrylonitrile-butadiene-styrene plastic (ABS), polyethylene terephthalate (PET), polybutylene terephthalate (PET), polyimides, polyetheretherketone (PEEK), polyetherketone (PEK), and polyoxymethylene plastic (POM, acetal), poly(ether sulfone), poly(methyl methacrylate), polyurethanes, polyvinyl chloride, and combinations thereof.

The production tool can be in the form of, for example, an endless belt (e.g., endless belt 200 shown in FIG. 1A), a sheet, a continuous sheet or web, a coating roll, a sleeve mounted on a coating roll, or die. If the production tool is in the form of a belt, sheet, web, or sleeve, it will have a contacting surface and a non-contacting surface. If the production tool is in the form of a roll, it will have a contacting surface only. The topography of the abrasive article formed by the method will have the inverse of the pattern of the contacting surface of the production tool. The pattern of the contacting surface of the production tool will generally be characterized by a plurality of cavities or recesses. The opening of these cavities can have any shape, regular or irregular, such as, for example, a rectangle, semi-circle, circle, triangle, square, hexagon, or octagon. The walls of the cavities can be vertical or tapered. The pattern formed by the cavities can be arranged according to a specified plan or can be random. Desirably, the cavities can butt up against one another.

The production tool can be made, for example, according to the following procedure. A master tool is first provided. The master tool is typically made from metal, e.g., nickel. The master tool can be fabricated by any conventional technique, such as, for example, engraving, hobbing, knurling, electroforming, diamond turning, or laser machining. If a pattern is desired on the surface of the production tool, the master tool should have the inverse of the pattern for the production tool on the surface thereof. The thermoplastic material can be embossed with the master tool to form the pattern. Embossing can be conducted while the thermoplastic material is in a flowable state. After being embossed, the thermoplastic material can be cooled to bring about solidification.

The production tool may also be formed by embossing a pattern into an already formed polymer film softened by heating. In this case, the film thickness may be less than the cavity depth.

This is advantageous in improving the flexibility of carriers having deep cavities.

The production tool can also be made of a cured thermosetting resin. A production tool made of thermosetting material can be made according to the following procedure. An uncured thermosetting resin is applied to a master tool of the type described previously. While the uncured resin is on the surface of the master tool, it can be cured or polymerized by heating such that it will set to have the inverse shape of the pattern of the surface of the master tool. Then, the cured thermosetting resin is removed from the surface of the master tool. The production tool can be made of a cured radiation curable resin, such as, for example acrylated urethane oligomers. Radiation cured production tools are made in the same manner as production tools made of thermosetting resin, with the exception that curing is conducted by means of exposure to radiation (e.g., ultraviolet radiation).

The production tool may have any thickness as long as it has sufficient depth to accommodate the abrasive particles and sufficient flexibility and durability for use in manufacturing processes. If the production tool comprises an endless belt, then production tool thicknesses of from about 0.5 to about 10 millimeters are typically useful; however, this is not a requirement.

The cavities may have any shape, and are typically selected depending on the specific application. Preferably, at least a portion (and more preferably a majority, or even all) of the cavities are shaped (i.e., individually intentionally engineered to have a specific shape and size), and more preferably are precisely-shaped. In some embodiments, the cavities have smooth walls and sharp angles formed by a molding process and having an inverse surface topography to that of a master tool (e.g., a diamond turned metal master tool roll) in contact with which it was formed. Preferably, at least some of the sidewalls taper inwardly from their respective cavity opening at the dispensing surface to the second opening at the back surface. More preferably, all of the sidewalls taper inwardly from the first opening at the dispensing surface to the second opening in the back surface of production tool 12.

Various methods can be employed to transfer the abrasive particles from cavities of the production tool to the resin coated backing or other substrate. These various methods may be employed, e.g., in combination with the techniques described herein in which a protruding portion of an abrasive article in a production tool is contacted by the outer surface of a transfer roll to displace the abrasive particle. In no particular order the various methods are:

1. Gravity assist where the production tool and dispensing surface is inverted for a portion of its machine direction travel and the abrasive particles fall out of the cavities under the force of gravity onto the resin coated backing. Typically in this method, the production tooling has two lateral edge portions with standoff members 260 (FIG. 2) located on the dispensing surface and that contact the resin coated backing at two opposed edges of the backing where resin has not been applied to hold the resin layer slightly above the dispensing surface of the production tooling as both wrap the abrasive particle transfer roll. Thus, there is a gap between the dispensing surface and the top surface of the resin layer on the resin coated backing so as to avoid transferring any resin to the dispensing surface of the production tooling. In one embodiment, the resin coated backing has two edge strips free of resin and a resin coated middle section while the dispensing surface can have two raised ribs extending in the longitudinal direction of the production tool for contact with the resin free edges of the backing In another embodiment, the abrasive particle transfer roll can have two raised ribs or rings on either end of the roll and a smaller diameter middle section with the production tooling contained within the smaller diameter middle section of the abrasive particle transfer roll as it wraps the abrasive particle transfer roll. The raised ribs or end rings on the abrasive particle transfer roll elevate the resin layer of the resin coated backing above the dispensing surface such that there is a gap between the two surfaces. Alternatively, raised posts distributed on the production tool surface could be used to maintain the gap between the two surfaces. 2. Vibration assist where the abrasive particle transfer roll or production tooling is vibrated by a suitable source such as an ultrasonic device to shake the abrasive particles out of the cavities and onto the resin coated backing. 3. Pressure assist where each cavity in the production tooling has two open ends or the back surface or the entire production tooling is suitably porous and the abrasive particle transfer roll has a plurality of apertures and an internal pressurized source of air. With pressure assist the production tooling may or may not be inverted. The abrasive particle transfer roll can also have movable internal dividers such that the pressurized air can be supplied to a specific arc segment or circumference of the roll to blow the abrasive particles out of the cavities and onto the resin coated backing at a specific location. In some embodiments, the abrasive particle transfer roll may also be provided with an internal source of vacuum without a corresponding pressurized region or in combination with the pressurized region typically prior to the pressurized region as the abrasive particle transfer roll rotates. The vacuum source or region can have movable dividers to direct it to a specific region or arc segment of the abrasive particle transfer roll. The vacuum can suck the abrasive particles firmly into the cavities as the production tooling wraps the abrasive particle transfer roll before subjecting the abrasive particles to the pressurized region of the abrasive particle transfer roll. This vacuum region be used, for example, with an abrasive particle removal member to remove excess abrasive particles from the dispensing surface or may be used to simply ensure the abrasive particles do not leave the cavities before reaching a specific position along the outer circumference of the abrasive particles transfer roll. 4. The various above listed embodiments are not limited to individual usage and they can be mixed and matched as necessary to more efficiently transfer the abrasive particles from the cavities to the resin coated backing.

Using examples of the disclosure may allow for the precise transfer and positioning of each abrasive particle onto the resin coated backing or other substrate by substantially reproducing the pattern of abrasive particles and their specific orientation as arranged in the production tool.

Examples of the disclosure relate to operation of system for make an abrasive article. The method generally involves the steps of filling the cavities in a production tool each with an individual abrasive particle. Aligning a filled production tool and a resin coated backing for transfer of the abrasive particles to the resin coated backing. Transferring the abrasive particles from the cavities onto the resin coated backing and removing the production tool from the aligned position with the resin coated backing. Thereafter the resin layer is cured, a size coat is applied and cured and the coated abrasive article is converted to sheet, disk, or belt form by suitable converting equipment.

The abrasive particles have sufficient hardness and surface roughness to function as abrasive particles in abrading processes. Preferably, the abrasive particles have a Mohs hardness of at least 4, at least 5, at least 6, at least 7, or even at least 8. Exemplary abrasive particles include crushed, shaped abrasive particles (e.g., shaped ceramic abrasive particles or shaped abrasive composite particles), and combinations thereof.

Examples of suitable abrasive particles include: fused aluminum oxide; heat-treated aluminum oxide; white fused aluminum oxide; ceramic aluminum oxide materials such as those commercially available under the trade designation 3M CERAMIC ABRASIVE GRAIN from 3M Company, St. Paul, Minn.; brown aluminum oxide; blue aluminum oxide; silicon carbide (including green silicon carbide); titanium diboride; boron carbide; tungsten carbide; garnet; titanium carbide; diamond; cubic boron nitride; garnet; fused alumina zirconia; iron oxide; chromia; zirconia; titania; tin oxide; quartz; feldspar; flint; emery; sol-gel-derived abrasive particles (e.g., including shaped and crushed forms); and combinations thereof. Further examples include shaped abrasive composites of abrasive particles in a binder matrix, such as those described in U.S. Pat. No. 5,152,917 (Pieper et al.). Many such abrasive particles, agglomerates, and composites are known in the art.

Examples of sol-gel-derived abrasive particles and methods for their preparation can be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.). It is also contemplated that the abrasive particles could comprise abrasive agglomerates such, for example, as those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S. Pat. No. 4,799,939 (Bloecher et al.). In some embodiments, the abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or other physical treatment (e.g., iron oxide or titanium oxide) to enhance adhesion of the abrasive particles to the binder. The abrasive particles may be treated before combining them with the binder, or they may be surface treated in situ by including a coupling agent to the binder.

Preferably, the abrasive particles comprise ceramic abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. The abrasive particles may be may be crushed or shaped, or a combination thereof.

Shaped ceramic abrasive particles composed of crystallites of alpha alumina, magnesium alumina spinel, and a rare earth hexagonal aluminate may be prepared using sol-gel precursor alpha alumina particles according to methods described in, for example, U.S. Pat. No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos. 2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.).

Alpha alumina-based shaped ceramic abrasive particles can be made according to well-known multistep processes. Briefly, the method comprises the steps of making either a seeded or non-seeded sol-gel alpha alumina precursor dispersion that can be converted into alpha alumina; filling one or more mold cavities having the desired outer shape of the shaped abrasive particle with the sol-gel, drying the sol-gel to form precursor shaped ceramic abrasive particles; removing the precursor shaped ceramic abrasive particles from the mold cavities; calcining the precursor shaped ceramic abrasive particles to form calcined, precursor shaped ceramic abrasive particles, and then sintering the calcined, precursor shaped ceramic abrasive particles to form shaped ceramic abrasive particles. The process will now be described in greater detail.

Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.); U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987 (Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and in U.S. Publ. Pat. Appln. No. 2009/0165394 A1 (Culler et al.).

Although there is no particularly limitation on the shape of the shaped ceramic abrasive particles, the abrasive particles are preferably formed into a predetermined shape by shaping precursor particles comprising a ceramic precursor material (e.g./, a boehmite sol-gel) using a mold, followed by sintering. The shaped ceramic abrasive particles may be shaped as, for example, pillars, pyramids, truncated pyramids (e.g., truncated triangular pyramids), and/or some other regular or irregular polygons. The abrasive particles may include a single kind of abrasive particles or an abrasive aggregate formed by two or more kinds of abrasive or an abrasive mixture of two or more kind of abrasives. In some embodiments, the shaped ceramic abrasive particles are precisely-shaped in that individual shaped ceramic abrasive particles will have a shape that is essentially the shape of the portion of the cavity of a mold or production tool in which the particle precursor was dried, prior to optional calcining and sintering.

Shaped ceramic abrasive particles used in the present disclosure can typically be made using tools (i.e., molds) cut using precision machining, which provides higher feature definition than other fabrication alternatives such as, for example, stamping or punching. Typically, the cavities in the tool surface have planar faces that meet along sharp edges, and form the sides and top of a truncated pyramid. The resultant shaped ceramic abrasive particles have a respective nominal average shape that corresponds to the shape of cavities (e.g., truncated pyramid) in the tool surface; however, variations (e.g., random variations) from the nominal average shape may occur during manufacture, and shaped ceramic abrasive particles exhibiting such variations are included within the definition of shaped ceramic abrasive particles as used herein.

In some embodiments, the base and the top of the shaped ceramic abrasive particles are substantially parallel, resulting in prismatic or truncated pyramidal shapes, although this is not a requirement. In some embodiments, the sides of a truncated trigonal pyramid have equal dimensions and form dihedral angles with the base of about 82 degrees. However, it will be recognized that other dihedral angles (including 90 degrees) may also be used. For example, the dihedral angle between the base and each of the sides may independently range from 45 to 90 degrees, typically 70 to 90 degrees, more typically 75 to 85 degrees.

As used herein in referring to shaped ceramic abrasive particles, the term “length” refers to the maximum dimension of a shaped abrasive particle. “Width” refers to the maximum dimension of the shaped abrasive particle that is perpendicular to the length. The terms “thickness” or “height” refer to the dimension of the shaped abrasive particle that is perpendicular to the length and width.

Preferably, the ceramic abrasive particles comprise shaped ceramic abrasive particles. Examples of sol-gel-derived shaped alpha alumina (i.e., ceramic) abrasive particles can be found in U.S. Pat. No. 5,201,916 (Berg); U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No. 5,984,988 (Berg). U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina abrasive particles that have been formed in a specific shape, then crushed to form shards that retain a portion of their original shape features. In some embodiments, sol-gel-derived shaped alpha alumina particles are precisely-shaped (i.e., the particles have shapes that are at least partially determined by the shapes of cavities in a production tool used to make them. Details concerning such abrasive particles and methods for their preparation can be found, for example, in U.S. Pat. No. 8,142,531 (Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); and U.S. Pat. No. 8,142,532 (Erickson et al.); and in U.S. Pat. Appl. Publ. Nos. 2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and 2013/0125477 (Adefris).

In some preferred embodiments, the abrasive particles comprise shaped ceramic abrasive particles (e.g., shaped sol-gel-derived polycrystalline alpha alumina particles) that are generally triangularly-shaped (e.g., a triangular prism or a truncated three-sided pyramid).

Shaped ceramic abrasive particles are typically selected to have a length in a range of from 1 micron to 15000 microns, more typically 10 microns to about 10000 microns, and still more typically from 150 to 2600 microns, although other lengths may also be used. In some embodiments, the length may be expressed as a fraction of the thickness of the bonded abrasive wheel in which it is contained. For example, the shaped abrasive particle may have a length greater than half the thickness of the bonded abrasive wheel. In some embodiments, the length may be greater than the thickness of the bonded abrasive cut-off wheel.

Shaped ceramic abrasive particles are typically selected to have a width in a range of from 0.1 micron to 3500 microns, more typically 100 microns to 3000 microns, and more typically 100 microns to 2600 microns, although other lengths may also be used.

Shaped ceramic abrasive particles are typically selected to have a thickness in a range of from 0.1 micron to 1600 microns, more typically from 1 micron to 1200 microns, although other thicknesses may be used.

In some embodiments, shaped ceramic abrasive particles may have an aspect ratio (length to thickness) of at least 2, 3, 4, 5, 6, or more.

The backing 36 can be a cloth, paper, film, nonwoven, scrim, or other web substrate used for abrasive articles. Resin layer 38 may be of any suitable composition. For example, such a coating may be a “make coat” as is commonly referred to in the abrasive arts. Such a make coat may be e.g. a phenolic resin or any of the other make coat compositions that are known. A make coat applicator can be, for example, a coater, a roll coater, a spray system, or a rod coater.

In various embodiments, the make coat layer is formed by at least partially curing a make layer precursor that is a curable tacky adhesive composition according to the present disclosure. The tacky curable adhesive composition includes resole phenolic resin and an aliphatic tack modifier, and the amount of resole phenolic resin includes from 60 to 98 weight percent of the combined weight of the resole phenolic resin and the aliphatic tack modifier.

Phenolic resins are generally formed by condensation of phenol and formaldehyde, and are usually categorized as resole or novolac phenolic resins. Novolac phenolic resins are acid catalyzed and have a molar ratio of formaldehyde to phenol of less than 1:1. Resole (also resol) phenolic resins can be catalyzed by alkaline catalysts, and the molar ratio of formaldehyde to phenol is greater than or equal to one, typically between 1.0 and 3.0, thus presenting pendant methylol groups. Alkaline catalysts suitable for catalyzing the reaction between aldehyde and phenolic components of resole phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all as solutions of the catalyst dissolved in water.

Resole phenolic resins are typically coated as a solution with water and/or organic solvent (e.g., alcohol). Typically, the solution includes about 70 percent to about 85 percent solids by weight, although other concentrations may be used.

Phenolic resins are well-known and readily available from commercial sources. Examples of commercially available resole phenolic resins useful in practice of the present disclosure include those marketed by Durez Corporation under the trade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those marketed by Ashland Chemical Co. of Bartow, Fla. under the trade designation AEROFENE (e.g., AEROFENE 295); and those marketed by Kangnam Chemical Company Ltd. of Seoul, South Korea under the trade designation PHENOLITE (e.g., PHENOLITE TD-2207).

In addition to the resole phenolic resin, the curable tacky binder precursor contains an aliphatic tack modifier. The curable tacky binder precursor contains from 60 to 98 weight percent, or 90 to 98 weight, percent of the resole phenolic resin based on the combined weight of the resole phenolic resin and the aliphatic tack modifier. Accordingly, the curable tacky binder precursor composition contains from 2 to 40 weight percent, or 2 to 10 weight percent, of the aliphatic tack modifier, based on the combined weight of the resole phenolic resin and the aliphatic tack modifier. The aliphatic tack modifier has the unexpected effect of modifying the tackiness of the resole phenolic resin, thereby resulting in the curable tacky binder precursor composition.

Examples of suitable aliphatic tack modifiers include: aliphatic rosins and aliphatic derivatives thereof aliphatic liquid hydrocarbon resins; aliphatic solid hydrocarbon resins; liquid natural rubber; hydrogenated polybutadiene; polytetramethylene ether glycol; isooctyl acrylate acrylic acid copolymers as described in U.S. Pat. No. 4,418,120 (Kealy et. al; and acrylic zwitterionic amphiphilic polymers as described in U.S. 2014/0170362 A1 (Ali et al.). Combinations of more than one resole phenolic resin and/or more than one aliphatic tack modifier may be used if desired.

Useful aliphatic rosins and aliphatic derivatives thereof include, for example, aliphatic esters of natural and modified rosins and the hydrogenated derivatives thereof (e.g., a glycerol ester of tall oil rosin marketed as PERMALYN 2085 and a glycerol ester of hydrogenated gum rosin marketed as FORAL 5-E, both available from Eastman Chemical Company, and an aliphatic rosin ester dispersion obtained as AQUATAC 6085 from Arizona Chemical, Jacksonville, Fla.), hydrogenated rosin resins (e.g., partially hydrogenated rosin is produced by Eastman Chemical Company as STAYBELITE-E and completely hydrogenated rosin is branded as FORAL AX-E), dimerized rosin resins (e.g., POLY-PALE partially dimerized rosin is a partially dimerized rosin product offered by Eastman Chemical Company), and aliphatic modified rosin resins (e.g., maleic anhydride modified rosin resins marketed as LEWISOL 28-M or LEWISOL 29-M).

Examples of aliphatic hydrocarbon resin tackifiers include tackifiers derived from liquid C5 feedstock by Lewis acid catalyzed polymerization, and hydrogenated derivatives thereof. Commercially available aliphatic hydrocarbon resin tackifiers include those marketed by Eastman Chemical Company, Kingsport, Tenn., under the trade designations PICCOTAC 1020, PICCOTAC 1095, PICCOTAC 1098, PICCOTAC 1100, and PICCOTAC 1115, and in hydrogenated forms as EASTOTAC H-100E, EASTOTAC H-115E and EASTOCTAC H-130E.

Liquid natural rubber is a modified form of natural rubber with a shorter polymeric chain. Many liquid natural rubbers are commercially available. Examples include liquid natural rubbers marketed by DPR industries, Coatesville, Pa., under the trade designations DPR 35, DPR 40, DPR 75, and DPR 400.

Hydrogenated polybutadienes are available commercially; for example, as KRATON LIQUID L1203 from Kraton Polymers US LLC, Houston, Tex., and as POLYTAIL from Mitsubishi International Polymer/Trade Corporation, Newark, N.J. Polytetramethylene ether glycol (PTMEG) is a waxy, white solid that melts to a clear, colorless viscous liquid near room temperature. PTMEG is produced by the catalyzed polymerization of tetrahydrofuran. Exemplary polytetramethylene ether glycols include those available under the trade designation TETRATHANE from Invista, Waynesboro, Va. (e.g., TETRATHANE 250, 650, 1000, 1400, 1800, 2000 and 2900). Useful copolymers of isooctyl acrylate and acrylic acid are described in U.S. Pat. No. 4,418,120 (Kealy et. al). Examples include copolymers of isooctyl acrylate (IOA) and acrylic acid (AA) wherein the weight ratio of IOA:AA is in the range of from 93:7 to 97:3; more preferably abut 95:5.

Useful aliphatic zwitterionic amphiphilic acrylic polymers are described in U.S. 2014/0170362 A1 (Ali et al.). Examples of useful zwitterionic amphiphilic acrylic polymers include the polymerized product of an anionic monomer that is acrylic acid, methacrylic acid, a salt thereof, or a blend thereof; an acrylate or methacrylate ester of an alcohol having between 8 and 12 carbons; and a cationic monomer that is an acrylate or methacrylate ester having alkylammonium functionality. Optionally, one or more additional monomers are included in the zwitterionic polymers of the invention. In some embodiments the anionic monomer is acrylic or methacrylic acid, the acid is converted either before or after polymerization to a corresponding carboxylate salt by neutralization. In some embodiments, the acrylic acid, methacrylic acid, or a salt thereof is a mixture of two or more thereof. In some embodiments, the acrylate or methacrylate ester is a mixture of two or more such esters; in some embodiments, the cationic monomer is a mixture of two or more such cationic monomers.

In some embodiments, the polymerized product of acrylic acid, methacrylic acid, a salt thereof or blend thereof is present in the zwitterionic polymer at about 0.2 wt % to 5 wt % based on the total weight of the polymer, or at about 0.5 wt % to 5 wt % of the zwitterionic polymer, or in various intermediate levels such as 0.3 wt %, 0.4 wt %, 0.6 wt %, 0.7 wt %, and all other such individual values represented by 0.1 wt % increments between 0.2 and 5.0 wt %, and in ranges spanning between any of these individual values in 0.1 wt % increments, such as 0.2 wt % to 0.9 wt %, 1.2 wt % to 3.1 wt %, and the like.

In some embodiments, the acrylate or methacrylate ester of an alcohol having between 8 and 12 carbons includes acrylate or methacrylate esters of linear, branched, or cyclic alcohols. While not intended to be limiting, examples of alcohols useful in the acrylate or methacrylate esters include octyl, isooctyl, nonyl, isononyl, decyl, undecyl, and dodecyl alcohol. In some embodiments, the alcohol is isooctyl alcohol. In some embodiments, the acrylate or methacrylate ester of an alcohol having between 8 and 12 carbons is a mixture of two or more such compounds.

In some embodiments, polymerized product of the acrylate or methacrylate ester of an alcohol having between 8 and 12 carbons is present in the zwitterionic polymer at about 50 wt % to 95 wt % of the total weight of the polymer, or at about 60 wt % to 90 wt % of the total weight of the polymer, or at about 75 wt % to 85 wt % of the total weight of the polymer, or in various intermediate levels such as 51 wt %, 52 wt %, 53 wt %, 54 wt %, and all other such values individually represented by 1 wt % increments between 50 wt % and 95 wt %, and in any range spanning between any of these individual values in 1 wt % increments, for example ranges such as about 54 wt % to 81 wt %, about 66 wt % to 82 wt %, about 77 wt % to 79 wt. 20%, and the like.

In some embodiments, the cationic monomer is an acrylate or methacrylate ester including an alkylammonium functionality. In some embodiments, the cationic monomer is a 2-(trialkylammonium)ethyl acrylate or a 2-(trialkylammonium)ethyl methacrylate. In such embodiments, the nature of the alkyl groups is not particularly limited; however, cost and practicality limit the number of useful embodiments. In embodiments, the 2-(trialkylammonium)ethyl acrylate or 2-(trialkylammonium)ethyl methacrylate is formed by the reaction of 2-(dimethylamino) ethyl acrylate or 2-(dimethylamino)ethyl methacrylate with an alkyl halide; in such embodiments, at least two of the three alkyl groups of the 2-(trialkylammonium)ethyl acrylate or 2-(trialkylammonium)ethyl methacrylate are methyl. In some such embodiments, all three alkyl groups are methyl groups. In other embodiments, two of the three alkyl groups are methyl and the third is a linear, branched, cyclic, or alicyclic group having between 2 and 24 carbon atoms, or between 6 and 20 carbon atoms, or between 8 and 18 carbon atoms, or 16 carbon atoms. In some embodiments, the cationic monomer is a mixture of two or more of these compounds.

The anion associated with the ammonium functionality of the cationic monomer is not particularly limited, and many anions are useful in connection with various embodiments of the invention. In some embodiments, the anion is a halide anion, such as chloride, bromide, fluoride, or iodide; in some such embodiments, the anion is chloride. In other embodiments the anion is BF4-, —N(SO2CF3)2, —O3SCF3, or —O3SC4F9. In other embodiments, the anion is methyl sulfate. In still other embodiments, the anion is hydroxide. In some embodiments, the one or more cationic monomers includes a mixture of two or more of these anions. In some embodiments, polymerization is carried out using 2-(dimethylamino)ethyl acrylate or 2-(dimethylamino)ethyl methacrylate, and the corresponding ammonium functionality is formed in situ by reacting the amino groups present within the polymer with a suitable alkyl halide to form the corresponding ammonium halide functionality. In other embodiments, the ammonium functional monomer is incorporated into the cationic polymer and then the anion is exchanged to provide a different anion. In such embodiments, ion exchange is carried out using any of the conventional processes known to and commonly employed by those having skill in the art.

In some embodiments, the polymerized product of the cationic monomer is present in the zwitterionic polymer at about 2 wt % to 45 wt % based on the total weight of the zwitterionic polymer, or at about 2 wt % to 35 wt % of the zwitterionic polymer, or at about 4 wt % to 25 wt % of the zwitterionic polymer, or at about 6 wt % to 15 wt % of the zwitterionic polymer, or at about 7 wt % to 10 wt % of the zwitterionic polymer, or in various intermediate levels such as 3 wt %, 5 wt %, 6 wt %, 8 wt %, and all other such individual values represented by 1 wt % increments between 2 wt % and 45 wt %, and in any range spanning these individual values in 1 wt % increments, such as 2 wt % to 4 wt %, 7 wt % to 38 wt %, 20 wt % to 25 wt %, and the like.

The curable tacky binder precursor material may also contain additives such as fibers, lubricants, wetting agents, thixotropic materials, surfactants, pigments, dyes, antistatic agents (e.g., carbon black, vanadium oxide, graphite, etc.), coupling agents (e.g., silanes, titanates, zircoaluminates, etc.), plasticizers, suspending agents, and the like. The amounts of these optional additives are selected to provide the preferred properties. The coupling agents can improve adhesion to the abrasive particles and/or filler. The binder chemistry may be thermally cured, radiation cured or combinations thereof. Additional details on binder chemistry may be found in U.S. Pat. No. 4,588,419 (Caul et al.), U.S. Pat. No. 4,751,138 (Tumey et al.), and U.S. Pat. No. 5,436,063 (Follett et al.).

The curable tacky binder precursor material may also contain filler materials or grinding aids, typically in the form of a particulate material. Typically, the particulate materials are inorganic materials. Examples of useful fillers for this disclosure include: metal carbonates (e.g., calcium carbonate (e.g., chalk, calcite, marl, travertine, marble and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (e.g., quartz, glass beads, glass bubbles and glass fibers) silicates (e.g., talc, clays, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate) metal sulfates (e.g., calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, carbon black, metal oxides (e.g., calcium oxide (lime), aluminum oxide, titanium dioxide), and metal sulfites (e.g., calcium sulfite).

The size layer precursor may be the same as or different than the make layer precursor. Examples of suitable thermosetting resins that may be useful for the size layer precursor include, for example, free-radically polymerizable monomers and/or oligomers, epoxy resins, acrylic resins, urethane resins, phenolic resins, urea-formaldehyde resins, melamine-formaldehyde resins, aminoplast resins, cyanate resins, or combinations thereof.

Useful binder precursors include thermally curable resins and radiation curable resins, which may be cured, for example, thermally and/or by exposure to radiation. The size layer precursor may also be modified various additives (e.g., as discussed above with respect to the make coat precursor). Catalysts and/or initiators may be added to thermosetting resins; for example, according to conventional practice and depending on the resin used.

In some embodiments, heat energy is applied to advance curing of the thermosetting resins (e.g., size layer precursor or curable tacky binder material precursor compositions according to the present disclosure). However, other sources of energy (e.g., microwave radiation, infrared light, ultraviolet light, visible light, may also be used). The selection will generally be dictated by the particular resin system selected.

The following clauses describe select embodiments of the present disclosure:

Clause 1. An abrasive particle transfer system comprising a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening; abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and an abrasive particle transfer roll having an outer surface, wherein the production tool is guided along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts the outer surface of the abrasive particle transfer roll to displace the abrasive particles.

Clause 2. The abrasive particle transfer system of clause 1, wherein the outer surface of the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool.

Clause 3. The abrasive particle transfer system of clause 2, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool at least approximately 1 mil.

Clause 4. The abrasive particle transfer system of clause 2, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool approximately 1 mil and approximately 25 mils.

Clause 5. The abrasive particle transfer system of any of clauses 1-4, wherein the web path of the production tool comprises a first web path, the system further comprising a resin coated backing guided along a second web path such that a resin layer of the resin coated backing is positioned facing the dispensing surface of the production tool and the production tool is positioned between the resin coated backing and the abrasive particle transfer roll.

Clause 6. The abrasive particle transfer system of clause 5, wherein the portion of the abrasive particles protruding from the back surface of the production tool contacts the abrasive particle transfer roll to urge the abrasive particles from the respective cavities onto the resin coating backing.

Clause 7. The abrasive particle transfer system of clause 6, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool to bring the abrasive particles into contact with the resin layer of the resin coated backing.

Clause 8. The abrasive particle transfer system of clause 6, wherein the resin coated backing and the dispensing surface of the production tool are separated by a gap where the abrasive particles are transferred from the plurality of cavities to the resin coated backing.

Clause 9. The abrasive particle transfer system of any of clauses 1-8, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening at least approximately 1 mil.

Clause 10. The abrasive particle transfer system of any of clauses 1-8, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening between approximately 1 mil and approximately 25 mils.

Clause 11. The abrasive particle transfer system of any of clause 1-10, wherein the abrasive particles are removably disposed within at least some of the cavities such that they do not extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.

Clause 12. The abrasive particle transfer system of any of clause 1-11, wherein the abrasive particles are removably disposed within at least some of the cavities such that they extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.

Clause 13. A method comprising providing a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening, wherein abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and guiding the production tool along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts an outer surface of an abrasive particle transfer roll to displace the abrasive particles.

Clause 14. The method of clause 13, wherein the outer surface of the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool.

Clause 15. The method of clause 14, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool at least approximately 1 mil.

Clause 16. The method of clause 14, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool approximately 1 mil and approximately 25 mils.

Clause 17. The method of any of clauses 13-16, wherein the web path of the production tool comprises a first web path, the method further comprising guiding a resin coated backing along a second web path such that a resin layer of the resin coated backing is positioned facing the dispensing surface of the production tool and the production tool is positioned between the resin coated backing and the abrasive particle transfer roll.

Clause 18. The method of clause 17, wherein the portion of the abrasive particles protruding from the back surface of the production tool contacts the abrasive particle transfer roll to urge the abrasive particles from the respective cavities onto the resin coating backing.

Clause 19. The method of clause 18, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool to bring the abrasive particles into contact with the resin layer of the resin coated backing.

Clause 20. The method of clause 18, wherein the resin coated backing and the dispensing surface of the production tool are separated by a gap where the abrasive particles are transferred from the plurality of cavities to the resin coated backing.

Clause 21. The method of any of clauses 13-20, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening at least approximately 1 mil.

Clause 22. The method of any of clauses 13-21, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening between approximately 1 mil and approximately 25 mils.

Clause 23. The method of any of clause 13-22, wherein the abrasive particles are removably disposed within at least some of the cavities such that they do not extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.

Clause 24. The method of any of clause 13-23, wherein the abrasive particles are removably disposed within at least some of the cavities such that they extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.

Various embodiments of the invention have been described. These and other embodiments are within the scope of the following claims. 

1. An abrasive particle transfer system comprising: a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening; abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and an abrasive particle transfer roll having an outer surface, wherein the production tool is guided along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts the outer surface of the abrasive particle transfer roll to displace the abrasive particles.
 2. The abrasive particle transfer system of claim 1, wherein the outer surface of the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool.
 3. The abrasive particle transfer system of claim 2, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool at least approximately 1 mil.
 4. The abrasive particle transfer system of claim 2, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool approximately 1 mil and approximately 25 mils.
 5. The abrasive particle transfer system of claim 1, wherein the web path of the production tool comprises a first web path, the system further comprising a resin coated backing guided along a second web path such that a resin layer of the resin coated backing is positioned facing the dispensing surface of the production tool and the production tool is positioned between the resin coated backing and the abrasive particle transfer roll.
 6. The abrasive particle transfer system of claim 5, wherein the portion of the abrasive particles protruding from the back surface of the production tool contacts the abrasive particle transfer roll to urge the abrasive particles from the respective cavities onto the resin coating backing.
 7. The abrasive particle transfer system of claim 6, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool to bring the abrasive particles into contact with the resin layer of the resin coated backing.
 8. The abrasive particle transfer system of claim 6, wherein the resin coated backing and the dispensing surface of the production tool are separated by a gap where the abrasive particles are transferred from the plurality of cavities to the resin coated backing.
 9. The abrasive particle transfer system of any of claims 1-8, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening at least approximately 1 mil.
 10. The abrasive particle transfer system of claim 1, wherein the portion of each particle of the abrasive particles protrudes from the back surface through the second opening between approximately 1 mil and approximately 25 mils.
 11. The abrasive particle transfer system of claim 1, wherein the abrasive particles are removably disposed within at least some of the cavities such that they do not extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.
 12. The abrasive particle transfer system of claim 1, wherein the abrasive particles are removably disposed within at least some of the cavities such that they extend beyond the dispensing surface prior to the portion of the abrasive particles protruding from the back surface of the production tool contacting the abrasive particle transfer roll.
 13. A method comprising: providing a production tool comprising a dispensing surface and a back surface opposite the dispensing surface, wherein the production tool has cavities formed therein, wherein, on a respective basis, each of the cavities extends from a first opening at the dispensing surface through the production tool to a second opening at the back surface, and wherein the second opening is smaller than the first opening, wherein abrasive particles removably disposed within at least some of the cavities such that a portion of each particle of the abrasive particles protrudes from the back surface through the second opening; and guiding the production tool along a web path such that the portion of the abrasive particles protruding from the back surface of the production tool contacts an outer surface of an abrasive particle transfer roll to displace the abrasive particles.
 14. The method of claim 13, wherein the outer surface of the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool.
 15. The method of claim 14, wherein the abrasive particle transfer roll contacts the portion of the abrasive particles protruding from the back surface of the production tool such that an opposite portion of each particle of the abrasive particles protrudes from the dispensing surface of the production tool approximately 1 mil and approximately 25 mils. 